Ellipse-forming compass



R. M. OMALLEY ELLIPSE-FORMING COMPASS Aug. 19,1962;

Filed Aug. 5, 1968 2 Sheets-Sheet 2 INVENTOR. F0551? 7' M @MAA/.Ey

/ TONY 3,461,564 ELLIPSE-FORMING COMPASS Robert M. OMalley, 11311 Osborne St., Lakeview Terrace, Calif. 91342 Filed Aug. 5, 1968, Ser. No. 750,103

Int. Cl. B431 11/04 U.S. Cl. 33-30 8 Claims ABSTRACT OF THE DISCLOSURE An ellipse-drawing or -scribing instrument having a post Afor nonrotational separable engagement with a surface and provided at its upper end with a linger-rotatable housing for a pivotally-mounted presettable disc `for adjusting the ratio of short and long diameters of an ellipse to :be scribed on such surface by means of slide means engageable by the periphery of said disc, said disc projecting and allowing a `slide of said slide means to retract as the housing is rotated, a marking or scriber leg connected by linkage to the `housing and moved relative to the post to scribe an ellipse conforming to the ratio adjustment, and an 'adjuster for setting the slides of said slide means to set the leg to the size of ellipse desired.

Background of the invention This compasstype ellipse marker or scriber may be used -for drafting as well as tool and machine layout purposes. The same, because it may be adjusted for ratio of ellipse axes as well as size of ellipse desired, is a complete, self-contained instrument, not requiring interchangeable templates, the present structure comprising a more yaccurately operable improvement of the ellipseforming compass disclosed in applicants Patent No. 3,005,544. Applicant believes that said patent comprises the best art in the present field.

An object of this invention is to provide an improved ellipse-forming compass that, by means of two simple adjustments, can be quickly set to draw or scribe ellipses having a wide-range ratio of long and short diameters, and -varying in size from a minimum to a maximum within the capacity of the instrument.

This invention also has for its objects to provide such means that are positive in operation, convenient in use, easily installed in a working position and easily disconnected therefrom, economical of manufacture, relatively simple, and of general superiority and serviceability.

The invention also comprises novel details of construction `and novel combintions and arrangements of parts, which will more fully appear in the course of the following description, which is based on the accompanying drawings. However, said drawings merely show, and the following description merely describes, one embodiment of the present invention, which is given by way of illustration or example only.

Summary of the invention The present invention comprises, generally, a post yadapted for nonrotational engagement with a surface 21 on which an ellipse is to be drawn or scribed, a housing 22 rotationally mounted on the upper end of said post, to turn horizontally on said post as an axis, presettable means 23 mounted in said housing and adjustable on a horizontal axis lfor adjusting the instrument to a desired ratio of long and short axes -of the ellipse to be formed 'and drawn or scribed on the surface 20, slide means 24 engaged by the means 23, projected thereby when the 'housing is rotated by finger manipulation and retracted by spring means to retain engagement with the slide means during such rotation of the housing, a marking or tracer 3,461,564 Patented Aug. 19, 1969 ICC leg y26, linkage 27 connecting said leg to the housing 22, means 28 interconnecting the slide means and said linkage to operate the latter and, thereby, extend or retract the leg 26 relative to the post 20, accordingly, and means 29 to adjust the slide means, thereby to adjust the size of the ellipse that is formed.

Brief description of the drawings In the drawings, like reference characters designate similar parts in the several views.

FIG. 1 is a side elevational view of an ellipse-forming compass according to the present invention, as viewed from one side, and shown in one operative position.

FIG. 2 is an enlarged View of the upper portion of the compass, with parts removed and others broken away.

FIG. 3 is a vertical sectional view of said upper portion, the plane of vsection being on the line 3-3 of FIG. 2.

FIG. 4 is a side elevational view of the upper portion gfctheZcompass as seen ifrom the side opposite to that of FIG. 5 is an edge view as seen from the right side of FIG. 4.

FIG. 6 is a vertical sectional view as taken on the line 6--6 of FIG. 4.

FIGS. 7 vand 8 are cross-sectional views, with parts removed, as taken on the line 7-7 of FIG. 2 and line 8*-8 of FIG. 3, respectively.

FIG. 9 is a view similar to FIG. 8 in another position.

FIG. 10 is' a vertical sectional View on the plane of line 6 6 and showing the compass as rotated 90 with respect to FIG, 6.

FIG. 11 is an enlarged sectional view of a portion of FIG. 10 with the compass adjusted to form a fuller ellipse zlilarl be formed by the compass when adjusted as in FIG. 12 is a cross-sectional view as taken on the line 12-12 of FIG. 2.

Description of the preferred embodiment The post 20 may comprise a rod or tu'be 30 provided on lts lower end with an axial pin 31 and a similar pin 32 in offset parallel relation to the pin 31. With the points on the ends of said pins penetrating the surface 21, said post 1s retained against rotation during operation of the instrument to draw ,or scribe an ellipse. At its upper end, the post 20 has a reduced neck portion 33, a further relduced portion 34 extending upwardly from the portion 33, an enlarged portion 35 extending from the portion 34, and a reduced post portion 36 extending from the portion 35. Said portions 33 and 34 lare shown as being cylindri cal to serve as bearings with which the lhofusing 22 and the slide means 24 are engaged so the latter may turn axially yon said post 20 and on a horizontal plan when the post is engaged, las described, with the surface 21.

The housing 22 has a lower end wall 37 provided with a bearing engaged with the reduced portion 23 of the post 20, an upright wall 38 extending from one end of the wall 37, and an upper end wall 39 coextensive with the Wall 37 and combining with said walls 37 and 38 to form a C- shaped `frame around an interior space 40. A short, downreaching extension 41 is provided on the upper end wall 39 on the side opposite to the wall 38. A knurled vertical extension- 42 is provided on the wall 39 coaxially with the mentioned bearing in the lower end wall and, therefore, of the post 20; said extension, when gripped between the ngers and turned, serves to turn said housing 22 and all elements carried thereby around the axis afforded by the shaft 20.

The presettable means 23 for setting the ratio of long and short axes `is shown as comprising a circular disc 43 that is formed to have a diametral horizontal axle 44 engaged in the post extension 36 and mounted thereon, a rotational knob mounted in a threaded seat 46 in the housing Wall 39 and, when rotationally adjusted by finger manipulation, moving vertically toward and from the axle 44 of the disc `43, a pin shaft 47 extending through said knob 45 coaxially with the post extension 36, a bracket 48 mounted on the lower end of said shaft 47, and a link 49 pivotally connected to said bracket at one end and at the other end to the disc` 43, offset from the axle 44 of said disc. The upper face of said knob 45 may be provided with peripheral degree graduations that are visible in the out-away space 50 formed in the housing wall 39.

By providing the knob 45 with a suitably large pitched threaded portion 51 engaged in the seat 46, a single rotation or less of the knob will serve to adjust the extended position of the knob so the link 49, as can he seen from FIGS. 2, 3, 6, 7, 8, 10 and 1l, will adjust the angular position tot" disc 43 to various angles whereby, in plan, the Idiameter of the disc along the axle 44 represents the major axis of the ellipse to be formed, and the projection, in plan, of said disc according to its adjusted position, represents the minor axis of said ellipse. Accordingly, by tracing around the peripheral edge 52 of the disc 43 with the tracer vertically applied, a true ellipse, according to the preset minor axis, is formed.

The slide means 24 has such an engagement with the periphery 52. Said means 24 is shown as comprising a tracer slide 53 that is guided to slide on the neck part 33 of the post 20, the same havin-g a vertical extension 54 that has the mentioned tracer engagement with the disc edge 52; and a size-adjustable slide 55 in which the slide 53 is nested and which is `guided by said slide 53, the slide 55 having a vertical extension 56 outward of and parallel to the slide extension 54. A horizontal threaded bore 57 is provided in the slide extension 56.

As shown in FIG. l2, the spring means 25, connected at one end 58 to the housing 22 and at the other end 59 to the slide 55, biases the latter, as well as the slide 53, in a direction to keep the extension 54 of slide 53 in -operative contact with the periphery 52 of the disc 43 during all rotated positions of the housing 22 around the axis of post 20.

As shown in FIGS 7, 8 and 9, the adjusting means 29 comprises a threaded stem 60 provided with an adjusting knob 61 on its outer end and with its inner end engaged in the bore 57. Said latter end is in impingement with the slide extension 54. It will be clear that slide 55 may be adjusted by the means 29 to be variously spaced from the slide 53. The lrneans 28 is shown as a bracket 62 that is provided Wit-h la slot 63. Said bracket is provided on the slide 55. The purpose of said cam slot will be later explained in connection with the operation of the linkage 27 and movement of the leg 26.

The leg 26, as shown in FIG. l, comprises an upper end 64 adapted for flat disposition outside a cover plate 65 afxed to the side of the housing 22 that is opposite to the out-away space 50. The lower end 66 of said leg may be formed as a pencil lead holder, as shown, as an inking port, or as a scriber, as desired, the same marking the ellipse through the linkage 27 according to movement of said linkage by the cam slot 63 as the slide 55 is projected by the disc 43 and retracted by the spring means 25 as the housing 22 and the leg are turned about the axis of the post 20. The leg 26 is made to be of a length that, when retracted to a position parallel to the post 20, such length, including any marking vor scribing means 67, brings the lower end of the latter to coincidence with the post pins 31 and 32. The linkage 27 is designed to so move said leg 26, according to the mentioned retraction and projection of the slide means 24, that said scribing means 67 retains level coincidence with pins 3l and 32 during all changes in the angle of the leg as the same forms an oval.

The linkage 27 comprises a link 68 having one end connected by a pivot 69 to the side of the housing 22 to which the plate 65 is applied, and the other end connected yby a pivot 76 to the iiat ripper portion 64 of the leg below its upper end; and a second link 71 connected by a pivot 72 to said plate 65 in spaced relation to the pivot 69, and connected by a pivot 73 to the mentioned end of t-he portion 64 of the leg 26. Said link 71, in offset relation to the pivot 72, is provided with a pin 73 that extends through an arcuate slot 74 in plate 65 and into slot 63 in bracket '62 Iof the slide 55. Said links 68 and 71, when swung outward from the folded position, as in FIGS. 3 and 4, move the upper end 64 ot the leg 26 in a direction away from the axis of the post 20. At the same time, due to the offset relationship of the pivots 69 and 72, the pivot 72, being located further from the side of the housing 22 at which the leg 26, when retracted, is disposed than is the pivot 69, the pivots 70 and 73, `from their vertically aligned relation when le-g 26 is retracted, move outwardly to an angled relation that brings the leg 26 to an angular disposition relative to the post Ztl, as can be seen in FIG. l. The links 68 and 7l. yare so proportioned that, in all angular positions of the leg 26, the scribing end 67 thereof remains at the level of the pins 31 and 32. Thus, as an ellipse is formed by rotational movement of the housing 22 and of the leg 26, said post may remain upright while the end 67 marks or scribes an ellipse.

The above-described angular movement of the link 71 is effected by the camming action of the slot 63 -upon the pin 73 on said link, when the slide 53, as the housing 22 is being rotated ,as described, is projected bv the peripheral edge 52 of disc 43 against the bias of the spring means 25. It will be seen that said slot 63 has a downwardly curved end portion that, as the slide 53 is being retracted, moves the pin 73 of link 71 in a downward direction that causes downward and outward pivotal movement of the said link and the above-described movement of the scribing leg 26. It will he clear that as the slide 53 retracts under bias of said spring means 25, a less curved or straightened end portion of the cam slot 63 pivotally moves the link 71 upwardly in a direction back toward its folded position. As a consequence, a full rotation of the housing 22 will cause an ellipse to be formed that has the major-minor ratio of the projected shape of the disc 43.

While the `foregoing has illustrated and described what is now contemplated to be the best mode of carrying out the invention, the construction is, of course, subject to modification without departing from the spirit and scope of the invention. Therefore, it is not desired to restrict the invention to the particular torrn of construction illustrated and described, but to cover all modications.

Having thus described the invention, what is claimed and desired to be secured by Letters Patent is:

ll. An ellipse-forming compass comprising:

(a) -a post adapted for nonrotational engagement with a surface on which an ellipse is to be drawn by the compass,

(b) a housing rotatably mounted on the upper end of `said post and adapted to be turned rotatably on said post as an axis,

(c) means mounted in said housing and presettable on a horizontal axis according to the major and minor axis ratio of the ellipse to be yformed 4on said surface,

(d) resiliently biased slide means in operative engagement with the presettable means and controlled thereby during rotation of the housing around the axis aorded bythe post,

(e) an ellipse-marking leg,

(f) linkage connecting the upper end of said leg to a side of said housing, and

(g) means interconnecting the slide means and the linkage to operate the latter to extend the leg from a position parallel to and alongside the post according to the movement of the slide means and to the present position of the presettable means during rotative movement of the housing around the post and of `the linkage and ellipse-marking leg, to mark an ellipse -by the latter having the same major-minor axis ratio to which the presettable means is set.

2. An ellipse-forming compass according to claim 1, including means to adjust the slide means to extend the marking leg to an initial angle relative to the post to vary the size of the ellipse being formed and yet retaining the major-minor axis ratio thereof.

3. An ellipse-forming `compass according to claim l in which the presettable means includes a circular disc that is adjustable on said axis so that -a projection of said disc, as adjusted, 'has the desired major-minor axis ratio, the mentioned slide means being engaged with the periphery of said disc to be projected thereby against the bias of the mentioned spring means during rotation of the housing, as mentioned.

`4. An ellipse-forming compass according to claim 3 in which means to set the disc includes a knob carried by the housing and manually angularly settable, as desited, the threaded engagement of the housing and knob, and link means interconnecting said knob and disc to change the angle, on its axis, of the latter according to the degree of projection of the knob due to its rotation on the threaded engagement.

5. An ellipse-forming compass according to claim 2 in which the linkage comprises a pair of links, each pivotally connected by one end thereof to the housing `and by the other end thereof to said upper end of the leg, the pivot of the link that is connected to the uppermost end of said leg end being spaced further from the leg, `when in the mentioned parallel position, than is the pivot of the other link, whereby, upon pivotal movement of the links downwardly on their axes, the leg is moved to angular position relative to the post according to the degree of link movement.

6. An ellipse-forming compass according to claim 5 in which the mentioned interconnecting means between the slide means and the `linkage is engaged with a pin extending from said upper link, a cam slot provided in said slide means controlling movement of said pin during projected and retracted movements of the slide means.

7. An ellipse-forming `compass according to claim 6 in which the slide means comprises a iirst slide in operative engagement with the presettable means, `a second slide in nesting relation to the rst slide, and manual means to regulate the position of the second slide relative to the rst slide, the mentioned cam being provided in the second slide and being, thereby, adjustable relative to the lirst slide and to the mentioned pin on the upper of the pair of links.

8. An ellipse-forming compass according to claim 1 in which the slide means comprises a pair of nesting slides, one operatively engaged with the presettable means and the other with the linkage, and means to bias the slides toward nested position.

References Cited UNITED STATES PATEN'IS 2,498,798 2/1950 Edwards.

HARRY N. HAROIAN, Primary Examiner 

